Đáp án:Giải thích các bước giải:
2$\frac{3}{4}$= $\frac{11}{4}$
4$\frac{3}{5}$ = $\frac{23}{5}$
12$\frac{11}{13}$ = $\frac{167}{13}$
3$\frac{4}{5}$ = $\frac{19}{5}$
11$\frac{12}{13}$ = $\frac{155}{13}$
3$\frac{3}{5}$ = $\frac{18}{5}$
bài 4:
3$\frac{3}{4}$+ 1$\frac{1}{2}$ = $\frac{15}{4}$+$\frac{3}{2}$ = $\frac{15}{4}$ + $\frac{6}{4}$ = $\frac{21}{4}$
4$\frac{5}{8}$ - 1$\frac{1}{4}$ =$\frac{37}{8}$ - $\frac{5}{4}$ = $\frac{37}{8}$ - $\frac{10}{8}$= $\frac{27}{8}$
3$\frac{1}{5}$ ÷ 2$\frac{1}{3}$ = $\frac{16}{5}$ ÷ $\frac{7}{3}$ = $\frac{16}{5}$ x $\frac{3}{7}$ = $\frac{48}{35}$
